MiR-26b-5p/TET3 regulates the osteogenic differentiation of human bone mesenchymal stem cells and bone reconstruction in female rats with calvarial defects.

BACKGROUND: MicroRNAs (miRNAs) play critical roles in the osteogenic differentiation of human bone mesenchymal stem cells (hBMSCs), but the mechanism by which miRNAs indirectly modulate osteogenesis remains unclear. Here, we explored the mechanism by which miRNAs indirectly modulate gene expression through histone demethylases to promote bone regeneration. METHODS AND RESULTS: Bioinformatics analysis was performed on hBMSCs after 7 days of osteogenic induction. The differentially expressed miRNAs were screened, and potential target mRNAs were identified. To determine the bioactivity and stemness of hBMSCs and their potential for bone repair, we performed wound healing, Cell Counting Kit-8 (CCK-8), real-time reverse transcription quantitative polymerase chain reaction (RT‒qPCR), alkaline phosphatase activity, alizarin red S (ARS) staining and radiological and histological analyses on SD rats with calvarial bone defects. Additionally, a dual-luciferase reporter assay was utilized to investigate the interaction between miR-26b-5p and ten-eleven translocation 3 (TET3) in human embryonic kidney 293T cells. The in vitro and in vivo results suggested that miR-26b-5p effectively promoted the migration, proliferation and osteogenic differentiation of hBMSCs, as well as the bone reconstruction of calvarial defects in SD rats. Mechanistically, miR-26b-5p bound to the 3' untranslated region of TET3 mRNA to mediate gene silencing. CONCLUSIONS: MiR-26b-5p downregulated the expression of TET3 to increase the osteogenic differentiation of hBMSCs and bone repair in rat calvarial defects. MiR-26b-5p/TET3 crosstalk might be useful in large-scale critical bone defects.

3-Hydroxyanthranilic Acid Delays Paralysis in Caenorhabditis elegans Models of Amyloid-Beta and Polyglutamine Proteotoxicity.

Age is the primary risk factor for neurodegenerative diseases such as Alzheimer's and Huntington's disease. Alzheimer's disease is the most common form of dementia and a leading cause of death in the elderly population of the United States. No effective treatments for these diseases currently exist. Identifying effective treatments for Alzheimer's, Huntington's, and other neurodegenerative diseases is a major current focus of national scientific resources, and there is a critical need for novel therapeutic strategies. Here, we investigate the potential for targeting the kynurenine pathway metabolite 3-hydroxyanthranilic acid (3HAA) using Caenorhabditis elegans expressing amyloid-beta or a polyglutamine peptide in body wall muscle, modeling the proteotoxicity in Alzheimer's and Huntington's disease, respectively. We show that knocking down the enzyme that degrades 3HAA, 3HAA dioxygenase (HAAO), delays the age-associated paralysis in both models. This effect on paralysis was independent of the protein aggregation in the polyglutamine model. We also show that the mechanism of protection against proteotoxicity from HAAO knockdown is mimicked by 3HAA supplementation, supporting elevated 3HAA as the mediating event linking HAAO knockdown to delayed paralysis. This work demonstrates the potential for 3HAA as a targeted therapeutic in neurodegenerative disease, though the mechanism is yet to be explored.

Novel enzymes for biodegradation of polycyclic aromatic hydrocarbons identified by metagenomics and functional analysis in short-term soil microcosm experiments.

Polycyclic aromatic hydrocarbons (PAHs) are highly toxic, carcinogenic substances. On soils contaminated with PAHs, crop cultivation, animal husbandry and even the survival of microflora in the soil are greatly perturbed, depending on the degree of contamination. Most microorganisms cannot tolerate PAH-contaminated soils, however, some microbial strains can adapt to these harsh conditions and survive on contaminated soils. Analysis of the metagenomes of contaminated environmental samples may lead to discovery of PAH-degrading enzymes suitable for green biotechnology methodologies ranging from biocatalysis to pollution control. In the present study, our goal was to apply a metagenomic data search to identify efficient novel enzymes in remediation of PAH-contaminated soils. The metagenomic hits were further analyzed using a set of bioinformatics tools to select protein sequences predicted to encode well-folded soluble enzymes. Three novel enzymes (two dioxygenases and one peroxidase) were cloned and used in soil remediation microcosms experiments. The experimental design of the present study aimed at evaluating the effectiveness of the novel enzymes on short-term PAH degradation in the soil microcosmos model. The novel enzymes were found to be efficient for degradation of naphthalene and phenanthrene. Adding the inorganic oxidant CaO2 further increased the degrading potential of the novel enzymes for anthracene and pyrene. We conclude that metagenome mining paired with bioinformatic predictions, structural modelling and functional assays constitutes a powerful approach towards novel enzymes for soil remediation.

Spectroscopic, electrochemical, and kinetic trends in Fe(III)-thiolate disproportionation near physiologic pH.

In addition to its primary oxygen-atom-transfer function, cysteamine dioxygenase (ADO) exhibits a relatively understudied anaerobic disproportionation reaction (ADO-Fe(III)-SR → ADO-Fe(II) + ½ RSSR) with its native substrates. Inspired by ADO disproportionation reactivity, we employ [Fe(tacn)Cl3] (tacn = 1,4,7-triazacyclononane) as a precursor for generating Fe(III)-thiolate model complexes in buffered aqueous media. A series of Fe(III)-thiolate model complexes are generated in situ using aqueous [Fe(tacn)Cl3] and thiol-containing ligands cysteamine, penicillamine, mercaptopropionate, cysteine, cysteine methyl ester, N-acetylcysteine, and N-acetylcysteine methyl ester. We observe trends in UV-Vis and electron paramagnetic resonance (EPR) spectra, disproportionation rate constants, and cathodic peak potentials as a function of thiol ligand. These trends will be useful in rationalizing substrate-dependent Fe(III)-thiolate disproportionation reactions in metalloenzymes.

Combined Effects of Clonal Hematopoiesis and Carotid Stenosis on Cardiovascular Mortality.

BACKGROUND: The expansion of hematopoietic stem cells caused by acquired somatic mutations (clonal hematopoiesis [CH]) is a novel cardiovascular risk factor. The prognostic value of CH in patients with carotid atherosclerosis remains to be evaluated. OBJECTIVES: This study assessed the prognostic significance of CH in patients with atherosclerosis as detected by ultrasound of the carotid artery. METHODS: We applied deep sequencing of selected genomic regions within the genes DNMT3A, TET2, ASXL1, and JAK2 to screen for CH in 968 prospectively collected patients with asymptomatic carotid atherosclerosis evaluated by duplex sonography. RESULTS: We detected clonal markers at variant allele frequency ≥2% in 133 (13.7%) of 968 patients (median age 69.2 years), with increasing prevalence at advanced age. Multivariate analyses including age and established cardiovascular risk factors revealed overall presence of CH to be significantly associated with increased risk of cardiovascular death (HR: 1.50; 95% CI: 1.12-2.00; P = 0.007), reflected also at the single gene level. The effect of CH was more pronounced in older patients and independent of the patients' inflammatory status as measured by high-sensitivity C-reactive protein. Simultaneous assessment of CH and degree of carotid stenosis revealed combined effects on cardiovascular mortality, depicted by a superior risk for patients with >50% stenosis and concomitant CH (adjusted HR: 1.60; 95% CI: 1.08-2.38; P = 0.020). CONCLUSIONS: CH status in combination with the extent of carotid atherosclerosis jointly predict long-term mortality. Determination of CH can provide additional prognostic information in patients with asymptomatic carotid atherosclerosis.

Understanding the stability of a plastic-degrading Rieske iron oxidoreductase system.

Rieske oxygenases (ROs) are a diverse metalloenzyme class with growing potential in bioconversion and synthetic applications. We postulated that ROs are nonetheless underutilized because they are unstable. Terephthalate dioxygenase (TPADO PDB ID 7Q05) is a structurally characterized heterohexameric α3ß3 RO that, with its cognate reductase (TPARED), catalyzes the first intracellular step of bacterial polyethylene terephthalate plastic bioconversion. Here, we showed that the heterologously expressed TPADO/TPARED system exhibits only ~300 total turnovers at its optimal pH and temperature. We investigated the thermal stability of the system and the unfolding pathway of TPADO through a combination of biochemical and biophysical approaches. The system's activity is thermally limited by a melting temperature (Tm) of 39.9°C for the monomeric TPARED, while the independent Tm of TPADO is 50.8°C. Differential scanning calorimetry revealed a two-step thermal decomposition pathway for TPADO with Tm values of 47.6 and 58.0°C (ΔH = 210 and 509 kcal mol-1, respectively) for each step. Temperature-dependent small-angle x-ray scattering and dynamic light scattering both detected heat-induced dissociation of TPADO subunits at 53.8°C, followed by higher-temperature loss of tertiary structure that coincided with protein aggregation. The computed enthalpies of dissociation for the monomer interfaces were most congruent with a decomposition pathway initiated by ß-ß interface dissociation, a pattern predicted to be widespread in ROs. As a strategy for enhancing TPADO stability, we propose prioritizing the re-engineering of the ß subunit interfaces, with subsequent targeted improvements of the subunits.

Identification and Expression Profile of NCED Genes in Arachis hypogaea L. during Drought Stress.

Peanut (Arachis hypogaea L.) is an important crop that provides essential proteins and oils for human and animal consumption. 9-cis-epoxycarotenoid dioxygenase (NCED) have been found can play a vital role in abscisic acid (ABA) biosynthesis and may be a response to drought stress. Until now, in Arachis hypogaea, no information about the NCED gene family has been reported and the importance of NCED-related drought tolerance is unclear. In this study, eight NCED genes in Arachis hypogaea, referred to as AhNCEDs, are distributed across eight chromosomes, with duplication events in AhNCED1 and AhNCED2, AhNCED3 and AhNCED4, and AhNCED6 and AhNCED7. Comparative analysis revealed that NCED genes are highly conserved among plant species, including Pisum sativum, Phaseolus vulgaris, Glycine max, Arabidopsis thaliana, Gossypium hirsutum, and Oryza sativa. Further promoter analysis showed AhNCEDs have ABA-related and drought-inducible elements. The phenotyping of Arachis hypogaea cultivars NH5 and FH18 demonstrated that NH5 is drought-tolerant and FH18 is drought-sensitive. Transcriptome expression analysis revealed the differential regulation of AhNCEDs expression in both NH5 and FH18 cultivars under drought stress. Furthermore, compared to the Arachis hypogaea cultivar FH18, the NH5 exhibited a significant upregulation of AhNCED1/2 expression under drought. To sum up, this study provides an insight into the drought-related AhNCED genes, screened out the potential candidates to regulate drought tolerance and ABA biosynthesis in Arachis hypogaea.

BRAF Mutations in Patients with Myeloid Neoplasms: A Cancer Center Multigene Next-Generation Sequencing Analysis Experience.

BRAF mutations are rare in myeloid neoplasms and are reported to be associated with poor treatment outcomes. The purpose of our study is to characterize BRAF mutations in myeloid neoplasms using a next-generation sequencing (NGS) panel based on the experiences of a single cancer center. We conducted a retrospective review of patients with myeloid neoplasms who underwent the HopeSeq studies between January 2018 and September 2023. A total of 14 patients with myeloid neoplasms carrying BRAF mutations were included in our cohort. The clinical, pathological, and molecular features of these patients were investigated. Our study indicates that BRAF mutations are rare in myeloid neoplasms, constituting only 0.53% (14/2632) of all myeloid neoplasm cases, with the most common BRAF mutation being BRAF V600E (4/14; 28.6%). Interestingly, we observed that six out of seven patients with acute myeloid leukemia (AML) exhibited AML with monocytic differentiation, and all the patients with AML exhibited an extremely poor prognosis compared to those without BRAF mutations. TET2 (5/14; 35.7%), ASXL1 (4/14; 28.6%), and JAK2 (4/14; 28.6%) were the three most frequently co-mutated genes in these patients. Moreover, we noted concurrent KMT2A gene rearrangement with BRAF mutations in three patients with AML (3/7; 42.9%). Our study suggests that although BRAF mutations are rare in myeloid neoplasms, they play a crucial role in the pathogenesis of specific AML subtypes. Furthermore, RAS pathway alterations, including BRAF mutations, are associated with KMT2A gene rearrangement in AML. However, these findings warrant further validation in larger studies.

TET2-STAT3-CXCL5 nexus promotes neutrophil lipid transfer to fuel lung adeno-to-squamous transition.

Phenotypic plasticity is a rising cancer hallmark, and lung adeno-to-squamous transition (AST) triggered by LKB1 inactivation is significantly associated with drug resistance. Mechanistic insights into AST are urgently needed to identify therapeutic vulnerability in LKB1-deficient lung cancer. Here, we find that ten-eleven translocation (TET)-mediated DNA demethylation is elevated during AST in KrasLSL-G12D/+; Lkb1L/L (KL) mice, and knockout of individual Tet genes reveals that Tet2 is required for squamous transition. TET2 promotes neutrophil infiltration through STAT3-mediated CXCL5 expression. Targeting the STAT3-CXCL5 nexus effectively inhibits squamous transition through reducing neutrophil infiltration. Interestingly, tumor-infiltrating neutrophils are laden with triglycerides and can transfer the lipid to tumor cells to promote cell proliferation and squamous transition. Pharmacological inhibition of macropinocytosis dramatically inhibits neutrophil-to-cancer cell lipid transfer and blocks squamous transition. These data uncover an epigenetic mechanism orchestrating phenotypic plasticity through regulating immune microenvironment and metabolic communication, and identify therapeutic strategies to inhibit AST.

Cell of origin epigenetic priming determines susceptibility to Tet2 mutation.

Hematopoietic stem cell (HSC) mutations can result in clonal hematopoiesis (CH) with heterogeneous clinical outcomes. Here, we investigate how the cell state preceding Tet2 mutation impacts the pre-malignant phenotype. Using an inducible system for clonal analysis of myeloid progenitors, we find that the epigenetic features of clones at similar differentiation status are highly heterogeneous and functionally respond differently to Tet2 mutation. Cell differentiation stage also influences Tet2 mutation response indicating that the cell of origin's epigenome modulates clone-specific behaviors in CH. Molecular features associated with higher risk outcomes include Sox4 that sensitizes cells to Tet2 inactivation, inducing dedifferentiation, altered metabolism and increasing the in vivo clonal output of mutant cells, as confirmed in primary GMP and HSC models. Our findings validate the hypothesis that epigenetic features can predispose specific clones for dominance, explaining why identical genetic mutations can result in different phenotypes.

Stable Interstrand Cross-Links Generated from the Repair of 1,N6-Ethenoadenine in DNA by α-Ketoglutarate/Fe(II)-Dependent Dioxygenase ALKBH2.

DNA cross-links severely challenge replication and transcription in cells, promoting senescence and cell death. In this paper, we report a novel type of DNA interstrand cross-link (ICL) produced as a side product during the attempted repair of 1,N6-ethenoadenine (εA) by human α-ketoglutarate/Fe(II)-dependent enzyme ALKBH2. This stable/nonreversible ICL was characterized by denaturing polyacrylamide gel electrophoresis analysis and quantified by high-resolution LC-MS in well-matched and mismatched DNA duplexes, yielding 5.7% as the highest level for cross-link formation. The binary lesion is proposed to be generated through covalent bond formation between the epoxide intermediate of εA repair and the exocyclic N6-amino group of adenine or the N4-amino group of cytosine residues in the complementary strand under physiological conditions. The cross-links occur in diverse sequence contexts, and molecular dynamics simulations rationalize the context specificity of cross-link formation. In addition, the cross-link generated from attempted εA repair was detected in cells by highly sensitive LC-MS techniques, giving biological relevance to the cross-link adducts. Overall, a combination of biochemical, computational, and mass spectrometric methods was used to discover and characterize this new type of stable cross-link both in vitro and in human cells, thereby uniquely demonstrating the existence of a potentially harmful ICL during DNA repair by human ALKBH2.

[Clinical Characteristics and Prognosis of Acute Myeloid Leukemia Patients with GATA2 Gene Mutation].

OBJECTIVE: To investigate the clinical characteristics, coexisting gene mutations and prognosis of acute myeloid leukemia (AML) patients with GATA2 gene mutation. METHODS: The clinical data of 370 newly diagnosed AML patients treated in our hospital from January 2008 to January 2021 was analyzed retrospectively, the next-generation sequencing technology was used to detect the mutated genes in those patients. The clinical characteristics of AML patients with GATA2 mutations, the co-mutated genes of GATA2 mutations, and the effect of GATA2 mutation on prognosis were analyzed. RESULTS: A total of 23 patients (6.2%) with GATA2 mutation was detected in 370 AML patients. Compared with GATA2 non-mutation group, patients in GATA2 mutation group were mostly normal karyotypes (P =0.037) and in low-risk cytogenetic stratification (P =0.028). The incidence of CEBPAdm and NRAS in GATA2 mutation group was significantly higher than that in GATA2 non-mutation group (P =0.010, P =0.009). There were no statistically significant differences between the two groups in terms of sex, age, white blood cell count (WBC), platelet count, hemoglobin, bone marrow (BM) blast, induction chemotherapy regimen and CR rate (P >0.05). Among the 23 patients with GATA2 mutation, the most common co-mutated genes were CEBPAdm, NRAS (both 39.1%), NPM1, FLT3, TET2, WT1 (all 17.4%), ASXL1 and IDH1 (both 13.0%). Survival analysis showed that there was no statistical difference in 5-year overall survival (OS) and leukemia-free survival (LFS) rates between patients with and without GATA2 mutations in whole cohort (n=370) (P =0.306, P =0.308). Among 306 patients without CEBPAdm, the 5-year OS and LFS rates in GATA2 mutation group showed an increasing trend compared with GATA2 non-mutation group, but the difference was not statistically significant (P =0.092, P =0.056). Among 64 patients with CEBPAdm, there was no statistically significant difference in 5-year OS rate between the GATA2 mutation group and the GATA2 non-mutation group (P =0.104), but the 5-year LFS rate of the GATA2 mutation group was significantly decreased (P =0.047). Among the 23 patients with GATA2 mutation, 16 cases received the "3+7" induction regimen, of which 12 cases received allogeneic hematopoietic stem cell transplantation (allo-HSCT); 7 cases received the "DCAG" induction regimen, of which 3 cases received allo-HSCT. The CR rate was not statistically different between the "3+7" regimen group and the "DCAG" regimen group (P =1.000). The 5-year OS rate and LFS rate in the transplantation group were significantly higher than the chemotherapy group (P =0.021, P =0.020). CONCLUSION: GATA2 mutation is more common in AML patients with normal karyotype and low-risk cytogenetic stratification, and it is significantly associated with CEBPAdm and NRAS co-mutations. The prognostic significance of GATA2 is influenced by CEBPAdm. The choice of "3+7" or "DCAG" induction regimen in patients with GATA2 mutation does not affect their CR rate, while the choice of allo-HSCT can significantly improved the prognosis compared with chemotherapy only.

A Rhodanese-Like Enzyme that Catalyzes Desulfination of Ergothioneine Sulfinic Acid.

Many actinobacterial species contain structural genes for iron-dependent enzymes that consume ergothioneine by way of O2-dependent dioxygenation. The resulting product ergothioneine sulfinic acid is stable under physiological conditions unless cleavage to sulfur dioxide and trimethyl histidine is catalyzed by a dedicated desulfinase. This report documents that two types of ergothioneine sulfinic desulfinases have evolved by convergent evolution. One type is related to metal-dependent decarboxylases while the other belongs to the superfamily of rhodanese-like enzymes. Pairs of ergothioneine dioxygenases (ETDO) and ergothioneine sulfinic acid desulfinase (ETSD) occur in thousands of sequenced actinobacteria, suggesting that oxidative ergothioneine degradation is a common activity in this phylum.

Enzymatic one-step synthesis of natural 2-pyrones and new-to-nature derivatives from coenzyme A esters.

The 2-pyrone moiety is present in a wide range of structurally diverse natural products with various biological activities. The plant biosynthetic routes towards these compounds mainly depend on the activity of either type III polyketide synthase-like 2-pyrone synthases or hydroxylating 2-oxoglutarate dependent dioxygenases. In the present study, the substrate specificity of these enzymes is investigated by a systematic screening using both natural and artificial substrates with the aims of efficiently forming (new) products and understanding the underlying catalytic mechanisms. In this framework, we focused on the in vitro functional characterization of a 2-pyrone synthase Gh2PS2 from Gerbera x hybrida and two dioxygenases AtF6'H1 and AtF6'H2 from Arabidopsis thaliana using a set of twenty aromatic and aliphatic CoA esters as substrates. UHPLC-ESI-HRMSn based analyses of reaction intermediates and products revealed a broad substrate specificity of the enzymes, enabling the facile "green" synthesis of this important class of natural products and derivatives in a one-step/one-pot reaction in aqueous environment without the need for halogenated or metal reagents and protective groups. Using protein modeling and substrate docking we identified amino acid residues that seem to be important for the observed product scope.

TET3 boosts hepatocyte autophagy and impairs non-alcoholic fatty liver disease by increasing ENPP1 promoter hypomethylation.

BACKGROUND: Dysregulated ecto-nucleotide pyrophosphatase/phosphodiesterase (ENPP) family occurs in metabolic reprogramming pathological processes. Nonetheless, the epigenetic mechanisms by which ENPP family impacts NAFLD, also known as metabolic dysfunction-associated steatotic liver disease (MASLD), is poorly appreciated. METHODS: We investigated the causes and consequences of ENPP1 promoter hypomethylation may boost NAFLD using NAFLD clinical samples, as well as revealed the underlying mechanisms using high-fat diet (HFD) + carbon tetrachloride (CCl4) induced mouse model of NAFLD and FFA treatment of cultured hepatocyte. RESULTS: Herein, we report that the expression level of ENPP1 are increased in patients with NAFLD liver tissue and in mouse model of NAFLD. Hypomethylation of ENPP1, is associated with the perpetuation of hepatocyte autophagy and liver fibrosis in the NAFLD. ENPP1 hypomethylation is mediated by the DNA demethylase TET3 in NAFLD liver fibrosis and hepatocyte autophagy. Additionally, knockdown of TET3 methylated ENPP1 promoter, reduced the ENPP1 expression, ameliorated the experimental NAFLD. Mechanistically, TET3 epigenetically promoted ENPP1 expression via hypomethylation of the promoter. Knocking down TET3 can inhibit the hepatocyte autophagy but an overexpression of ENPP1 showing rescue effect. CONCLUSIONS: We describe a novel epigenetic mechanism wherein TET3 promoted ENPP1 expression through promoter hypomethylation is a critical mediator of NAFLD. Our findings provide new insight into the development of preventative measures for NAFLD.

Genetic redundancy in the naphthalene-degradation pathway of Cycloclasticus pugetii strain PS-1 enables response to varying substrate concentrations.

Polycyclic aromatic hydrocarbon (PAH) contamination in marine environments range from low-diffusive inputs to high loads. The influence of PAH concentration on the expression of functional genes [e.g. those encoding ring-hydroxylating dioxygenases (RHDs)] has been overlooked in PAH biodegradation studies. However, understanding marker-gene expression under different PAH loads can help to monitor and predict bioremediation efficiency. Here, we followed the expression (via RNA sequencing) of Cycloclasticus pugetii strain PS-1 in cell suspension experiments under different naphthalene (100 and 30 mg L-1) concentrations. We identified genes encoding previously uncharacterized RHD subunits, termed rhdPS1α and rhdPS1ß, that were highly transcribed in response to naphthalene-degradation activity. Additionally, we identified six RHD subunit-encoding genes that responded to naphthalene exposure. By contrast, four RHD subunit genes were PAH-independently expressed and three other RHD subunit genes responded to naphthalene starvation. Cycloclasticus spp. could, therefore, use genetic redundancy in key PAH-degradation genes to react to varying PAH loads. This genetic redundancy may restrict the monitoring of environmental hydrocarbon-degradation activity using single-gene expression. For Cycloclasticus pugetii strain PS-1, however, the newly identified rhdPS1α and rhdPS1ß genes might be potential target genes to monitor its environmental naphthalene-degradation activity.

Catalytic-dependent and -independent roles of TET3 in the regulation of specific genetic programs during neuroectoderm specification.

The ten-eleven-translocation family of proteins (TET1/2/3) are epigenetic regulators of gene expression. They regulate genes by promoting DNA demethylation (i.e., catalytic activity) and by partnering with regulatory proteins (i.e., non-catalytic functions). Unlike Tet1 and Tet2, Tet3 is not expressed in mouse embryonic stem cells (ESCs) but is induced upon ESC differentiation. However, the significance of its dual roles in lineage specification is less defined. By generating TET3 catalytic-mutant (Tet3m/m) and knockout (Tet3-/-) mouse ESCs and differentiating them to neuroectoderm (NE), we identify distinct catalytic-dependent and independent roles of TET3 in NE specification. We find that the catalytic activity of TET3 is important for activation of neural genes while its non-catalytic functions are involved in suppressing mesodermal programs. Interestingly, the vast majority of differentially methylated regions (DMRs) in Tet3m/m and Tet3-/- NE cells are hypomethylated. The hypo-DMRs are associated to aberrantly upregulated genes while the hyper-DMRs are linked to downregulated neural genes. We find the maintenance methyltransferase Dnmt1 as a direct target of TET3, which is downregulated in TET3-deficient NE cells and may contribute to the increased DNA hypomethylation. Our findings establish that the catalytic-dependent and -independent roles of TET3 have distinct contributions to NE specification with potential implications in development.

Functional Analysis of ß-Carotene Oxygenase 2 (BCO2) Gene in Yesso Scallop (Patinopecten yessoensis).

Carotenoids are essential nutrients for humans and animals, and carotenoid coloration represents an important meat quality parameter for many farmed animals. Increasingly, studies have demonstrated that vertebrate carotenoid cleavage oxygenases (CCOs) are essential enzymes in carotenoid metabolism and are therefore potential candidate genes for improving carotenoid deposition. However, our understanding of carotenoid bioavailability and CCOs functions in invertebrates, particularly marine species, is currently quite limited. We previously identified that a CCO homolog, PyBCO-like 1, was the causal gene for carotenoid coloration in the 'Haida golden scallop', a variety of Yesso scallop (Patinopecten yessoensis) characterized by carotenoid enrichment. Here, we found that another CCO-encoding gene named PyBCO2 (ß-carotene oxygenase 2) was widely expressed in P. yessoensis organs/tissues, with the highest expression in striated muscle. Inhibiting BCO2 expression in P. yessoensis through RNA interference led to increased carotenoid (pectenolone and pectenoxanthin) deposition in the striated muscle, and the color of the striated muscle changed from white to light orange. Our results indicate that PyBCO2 might be a candidate gene used for improving carotenoid content in normal Yesso scallops, and also in 'Haida golden scallops'.

[Gene Profile and Clinical Significance of Concomitant Mutations in CN-AML Patients with CEBPA Mutation].

OBJECTIVE: To analyze the occurrence of concomitant gene mutations in cytogenetically normal acute myeloid leukemia (CN-AML) patients with CEBPA mutation and its impact on the clinical characteristics and prognosis of the patients. METHODS: 151 newly diagnosed patients with CN-AML in the Second Hospital of Shanxi Medical University from June 2013 to June 2020 were analyzed retrospectively. 34 common genetic mutations associated with hematologic malignancies were detected by next-generation sequencing technology. The occurrence of concomitant gene mutations in patients with CEBPA positive and negative groups was compared, and the correlation between concomitant mutations in different functional groups and the clinical characteristics and prognosis of CN-AML patients with CEBPA mutation was analyzed. RESULTS: In 151 patients with CN-AML, 55 (36.42%) were positive for CEBPA mutation (including 36 cases of CEBPAdm and 19 cases of CEBPAsm), of which 41 (74.55%) had co-mutations with other genes. The main mutated genes were GATA2 (25.45%, 14/55), TET2 (21.82%, 12/55), FLT3 (20.00%, 11/55), NRAS (12.73%, 7/55) and WT1 (9.09%, 9/55), etc. Some cases had two or more concomitant gene mutations. Grouping the mutant genes according to their functions showed that CEBPA+ group had lower mutation rates of histone methylation (P =0.002) and chromatin modification genes (P =0.002, P =0.033), and higher mutation rates of transcription factors (P =0.037) than CEBPA- group. In 55 patients with CEBPA+ CN-AML, the platelet count at diagnosis in signaling pathway gene mutation-positive group was lower than that in the mutation-negative group (P =0.005), the proportion of bone marrow blasts in transcription factor mutation-positive group was higher than that in the mutation-negative group (P =0.003), and the onset age in DNA methylation gene mutation-positive group and chromatin modifier mutation-positive group was older than that in the mutation-negative group, respectively (P =0.002, P =0.008). DFS of CEBPA+ CN-AML patients in signaling pathway gene mutation group was shorter than that in signaling pathway gene mutation-negative group (median DFS: 12 months vs not reached) (P =0.034). Compared with DNA methylation gene mutation-negative group, CEBPA+ CN-AML patients with DNA methylation gene mutation had lower CR rate (P =0.025) significantly shorter OS and DFS (median OS: 20 months vs not reached, P =0.006; median DFS: 15 months vs not reached, P =0.049). OS in patients with histone methylation gene mutation was significantly shorter than that in the histone methylation gene mutation-negative group (median OS: 12 months vs 40 months) (P =0.008). Multivariate analysis of prognostic factors showed that the proportion of bone marrow blasts (P =0.046), concomitant DNA methylation gene mutation (P =0.006) and histone methylation gene mutation (P =0.036) were independent risk factors affecting the prognosis. CONCLUSION: CN-AML patients with CEBPA mutation have specific concomitant gene profile, and the concomitant mutations of different functional genes have a certain impact on the clinical characteristics and prognosis of the patients.

A negative feedback loop between TET2 and leptin in adipocyte regulates body weight.

Ten-eleven translocation (TET) 2 is an enzyme that catalyzes DNA demethylation to regulate gene expression by oxidizing 5-methylcytosine to 5-hydroxymethylcytosine, functioning as an essential epigenetic regulator in various biological processes. However, the regulation and function of TET2 in adipocytes during obesity are poorly understood. In this study, we demonstrate that leptin, a key adipokine in mammalian energy homeostasis regulation, suppresses adipocyte TET2 levels via JAK2-STAT3 signaling. Adipocyte Tet2 deficiency protects against high-fat diet-induced weight gain by reducing leptin levels and further improving leptin sensitivity in obese male mice. By interacting with C/EBPα, adipocyte TET2 increases the hydroxymethylcytosine levels of the leptin gene promoter, thereby promoting leptin gene expression. A decrease in adipose TET2 is associated with obesity-related hyperleptinemia in humans. Inhibition of TET2 suppresses the production of leptin in mature human adipocytes. Our findings support the existence of a negative feedback loop between TET2 and leptin in adipocytes and reveal a compensatory mechanism for the body to counteract the metabolic dysfunction caused by obesity.