Loss of SETD1B results in the redistribution of genomic H3K4me3 in the oocyte

SummaryHistone 3 lysine 4 trimethylation (H3K4me3) is an epigenetic mark found at gene promoters and CpG islands. H3K4me3 is essential for mammalian development, yet mechanisms underlying its genomic targeting are poorly understood. H3K4me3 methyltransferases SETD1B and MLL2 are essential for oogenesis. We investigated changes in H3K4me3 in Setd1b conditional knockout (cKO) GV oocytes using ultra-low input ChIP-seq, in conjunction with DNA methylation and gene expression analysis. Setd1b cKO oocytes showed a redistribution of H3K4me3, with a marked loss at active gene promoters associated with downregulated gene expression. Remarkably, many regions gained H3K4me3 in Setd1b cKOs, in particular those that were DNA hypomethylated, transcriptionally inactive and CpG-rich - hallmarks of MLL2 targets. Thus, loss of SETD1B appears to enable enhanced MLL2 activity. Our work reveals two distinct, complementary mechanisms of genomic targeting of H3K4me3 in oogenesis, with SETD1B linked to gene expression in the oogenic program and MLL2 to CpG content.

MondoA regulates gene expression in cholesterol biosynthesis-associated pathways required for zebrafish epiboly

The glucose-sensing Mondo pathway regulates expression of metabolic genes in mammals. Here, we characterized its function in the zebrafish and revealed an unexpected role of this pathway in vertebrate embryonic development. We showed that knockdown of mondoa impaired the early morphogenetic movement of epiboly in zebrafish embryos and caused microtubule defects. Expression of genes in the terpenoid backbone and sterol biosynthesis pathways upstream of pregnenolone synthesis was coordinately downregulated in these embryos, including the most downregulated gene nsdhl. Loss of Nsdhl function likewise impaired epiboly, similar to MondoA loss of function. Both epiboly and microtubule defects were partially restored by pregnenolone treatment. Maternal-zygotic mutants of mondoa showed perturbed epiboly with low penetrance and compensatory changes in the expression of terpenoid/sterol/steroid metabolism genes. Collectively, our results show a novel role for MondoA in the regulation of early vertebrate development, connecting glucose, cholesterol and steroid hormone metabolism with early embryonic cell movements.

N-MYC Downstream Regulated Gene 4 (NDRG4), a Frequent Downregulated Gene through DNA Hypermethylation, plays a Tumor Suppressive Role in Esophageal Adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) has been rising dramatically in the past few decades in the United States and Western world. The N-myc downregulated gene 4 (NDRG4) belongs to the human NDRG family. In this study, we aimed to identify the expression levels, regulation, and functions of NDRG4 in EAC. Using an integrative epigenetic approach, we identified genes showing significant downregulation in EAC and displaying upregulation after 5-Aza-deoxycitidine. Among these genes, likely to be regulated by DNA methylation, NDRG4 was among the top 10 candidate genes. Analyses of TCGA (The Cancer Genome Atlas) and GEO (Gene Expression Omnibus) data sets and EAC tissue samples demonstrated that NDRG4 was significantly downregulated in EAC (p < 0.05). Using Pyrosequencing technology for quantification of DNA methylation, we detected that NDRG4 promoter methylation level was significantly higher in EAC tissue samples, as compared to normal esophagus samples (p < 0.01). A strong inverse correlation between NDRG4 methylation and its gene expression levels (r = −0.4, p < 0.01) was observed. Treatment with 5-Aza restored the NDRG4 expression, confirming that hypermethylation is a driving force for NDRG4 silencing in EAC. Pathway and gene set enrichment analyses of TCGA data suggested that NDRG4 is strongly associated with genes related to cell cycle regulation. Western blotting analysis showed significant downregulation of Cyclin D1, CDK4 and CDK6 in EAC cells after overexpression of NDRG4. Functionally, we found that the reconstitution of NDRG4 resulted in a significant reduction in tumor cell growth in two-dimensional (2D) and three-dimensional (3D) organotypic culture models and inhibited tumor cell proliferation as indicated by the EdU (5-ethynyl-2′-deoxyuridine) proliferation assay.

Myxovirus Resistance Protein 1 (MX1), a Novel HO-1 Interactor, Tilts the Balance of Endoplasmic Reticulum Stress towards Pro-Death Events in Prostate Cancer

The inflammatory tumor microenvironment is a fertile niche accelerating prostate cancer (PCa). We have reported that heme-oxygenase (HO-1) had a strong anti-tumoral effect in PCa. We previously undertook an in-depth proteomics study to build the HO-1 interactome in PCa. In this work, we used a bioinformatics approach to address the biological significance of HO-1 interactors. Open-access PCa datasets were mined to address the clinical significance of the HO-1 interactome in human samples. HO-1 interactors were clustered into groups according to their expression profile in PCa patients. We focused on the myxovirus resistance gene (MX1) as: (1) it was significantly upregulated under HO-1 induction; (2) it was the most consistently downregulated gene in PCa vs. normal prostate; (3) its loss was associated with decreased relapse-free survival in PCa; and (4) there was a significant positive correlation between MX1 and HMOX1 in PCa patients. Further, MX1 was upregulated in response to endoplasmic reticulum stress (ERS), and this stress triggered apoptosis and autophagy in PCa cells. Strikingly, MX1 silencing reversed ERS. Altogether, we showcase MX1 as a novel HO-1 interactor and downstream target, associated with ERS in PCa and having a high impact in the clinical setting.

Downregulated Gene Expression Spectrum and Immune Responses Changed During the Disease Progression in Patients With COVID-19

Background The World Health Organization characterizes novel coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as a pandemic. Here, we investigated the clinical, cytokine levels; T-cell proportion; and related gene expression occurring in patients with COVID-19 on admission and after initial treatment. Methods Eleven patients diagnosed with COVID-19 with similar initial treatment regimens were enrolled in the hospital. Plasma cytokine, peripheral T cell proportions, and microfluidic quantitative polymerase chain reaction analyses for gene expression were conducted. Results Five patients with mild and 6 with severe disease were included. Cough and fever were the primary symptoms in the 11 COVID-19 cases. Older age, higher neutrophil count, and higher C-reactive protein levels were found in severe cases. IL-10 level significantly varied with disease progression and treatment. Decreased T-cell proportions were observed in patients with COVID-19, especially in severe cases, and all were returned to normal in patients with mild disease after initial treatment, but only CD4+ T cells returned to normal in severe cases. The number of differentially expressed genes (DEGs) increased with the disease progression, and decreased after initial treatment. All downregulated DEGs in severe cases mainly involved Th17-cell differentiation, cytokine-mediated signaling pathways, and T-cell activation. After initial treatment in severe cases, MAP2K7 and SOS1 were upregulated relative to that on admission. Conclusions Our findings show that a decreased T-cell proportion with downregulated gene expression related to T-cell activation and differentiation occurred in patients with severe COVID-19, which may help to provide effective treatment strategies for COVID-19.

Population Specific Adaptations in Venom Production to Abiotic Stressors in a Widely Distributed Cnidarian

Nematostella vectensis is a sea anemone (Actiniaria, Cnidaria) inhabiting estuaries over a broad geographic range where environmental conditions such as temperatures and salinity vary widely. In cnidarians, antagonistic interactions with predators and prey are mediated by their venom, which may be metabolically expensive. In this study, we challenged Nematostella polyps with heat, salinity, UV light stressors and a combination of all three to determine how abiotic stressors impact toxin expression for individuals collected across this species’ range. Transcriptomics and proteomics revealed that the highly abundant toxin Nv1 was the most downregulated gene under heat stress conditions in multiple populations. Physiological measurements demonstrated that venom is metabolically costly to produce suggesting that downregulating venom expression under stressful conditions may be advantageous. Strikingly, under a range of abiotic stressors, individuals from different geographic locations along this latitudinal cline modulate venom production levels differently in a pattern reflecting local adaptation.

Dendrobium officinale Polysaccharides Inhibit 1-Methyl-2-Nitro-1-Nitrosoguanidine Induced Precancerous Lesions of Gastric Cancer in Rats through Regulating Wnt/β-Catenin Pathway and Altering Serum Endogenous Metabolites

Dendrobium officinale is a herb in traditional Chinese medicine where D. officinale polysaccharides (DOP) are the main active ingredient. This study aimed at evaluating DOP efficiency at inhibiting 1-Methyl-2-nitro-1-nitrosoguanidine (MNNG) induced precancerous lesions of gastric cancer (PLGC) in rats through the Wnt/b-catenin pathway and analyzing the variations of serum endogenous metabolites. PLGC was established in male Sprague-Dawley (SD) rats by administering 150 μg/mL MNNG in drinking water for 7 months and giving 0.1 mL of 10% NaCl once weekly during the initial 20 weeks. Treatment with DOP inhibited the progress of PLGC through decreasing the expression of β-catenin by immunohistochemical analysis. The futher study indicated DOP downregulated gene expression of Wnt2β, Gsk3β, PCNA, CyclinD1, and β-catenin, as well as protein expression of Wnt2β, PCNA, and β-catenin. On the other hand, there were nine endogenous metabolites identified after the DOP treatment. Among these, the most significant one is betaine because of its strong antioxidant activity, leading to an anti-tumor effect. DOP can inhibit MNNG-induced PLGC models via regulating Wnt/β-catenin pathway and by changing endogenous metabolites.